In both the Anima core rulebook and in Beyond the Dream, the history presented in both respective chapters is given to us by an enigmatic individual who remarks on the fact that they've been there through every event, witnessing the history of Gaia.

From the core book - "All of them can feel it. It has begun. And all of the things I have told... I have seen them. Because I never forgot. That is my damnation."

From Beyond the Dream - "The dark legacy that man inherits is on the verge of fruition. Nothing is over. Deep down, this story has only just begun. And as I was present at the beginning…
So shall I be here to witness its end."

Do we have any clue who this individual is?

No clue. It is possible that it is only being used as a writing technique to spice up the book.

Yep. I always assumed it was an inside joke for the writier.

It's Doctor Who, the Timelord

So that's what he does during his off time between episodes....